The present invention relates generally to an input device for a portable personal computer ("PC"). More particularly, this invention relates to a trackball or mouse device that is used to provide input signals to control a pointer or arrow on the screen of a PC. Still more particularly, this invention relates to system for selectively enabling or disabling a trackball device during operation.
The trend in the portable PC market is for smaller and lighter computers that can easily be carried and stored by a user. Consumers of portable PC's, however, also are demanding more computing power and additional features that rival traditional desk-top computers. Thus, to satisfy consumers, portable PC manufacturers are providing more computing power, with additional features, on more compact units.
One of the features that is especially desired on computers is a trackball or mouse device, which can facilitate the use of certain operating systems and software programs. To minimize the number of accessories that must be carried with the portable computer, and also to minimize the number of external connections, certain portable computer manufacturers provide an integral trackball device adjacent the keyboard of the personal computer, as shown for example in FIG. 1. Because of the space restrictions on the more compact computers, the trackball in some of these computers is located next to the space bar, in the region where the user may tend to rest his or her hands during keyboard operation.
Providing a trackball adjacent the keyboard, however, increases the possibility of operator errors. Because of the proximity of the trackball to the keyboard, a user may inadvertently activate the trackball while using the keyboard. In certain operating systems or software programs, this inadvertent activation of the trackball can have disastrous results. In word processing programs, for example, activating the trackball may initiate text blocking features. If a delete key is subsequently activated, the text could be erased accidently.
Typically, the trackball is activated during system initialization or "boot-up." Thus, if the trackball is disabled by the user, the only way to enable the trackball is to reboot the system. In addition, the trackball must be activated before most software packages or operating systems are initiated. As a result of these operating parameters, typically the trackball is left enabled during operation with the hope that no operator errors will result.
It would be desirable to develop a system in which the trackball can be selectively enabled or disabled at any time through the selection of a "hot" key or key combination. Although the advantages of such a feature are apparent, to date no one has developed a system that can quickly enable and disable a trackball during system operation.